int LEDlight = 0;
int num = 5;
void setup() {
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
}

void loop() {
  analogWrite(12, LEDlight);
  analogWrite(11, LEDlight);
  LEDlight = LEDlight + num;
  
  if(LEDlight === 0 || LEDlight == 300)
  {
    num = -num;
  }
  
  delay(50);
}
